1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably holding an electrical part such as semiconductor device, called hereinlater "IC package", particularly having improved structures of a contact pin separated from or contacted to the electrical part and a movable plate for displacing the contact pin.
2. Prior Art of the Invention
In this art field, there is known an IC socket as "socket for an electrical part" for detachably holding an IC package as "electrical part" such as disclosed in the Japanese Utility Model Publication No. HEI 6-44050.
To such known IC socket, a number of contact pins are arranged, and as shown in FIGS. 7A and 7B, in which only one contact pin 1 is shown, the contact pin 1 is formed with a pair of clamping pieces 1a each being formed with a contact portion 1b which is contacted to and separated from a connection pin 2 of the IC package. The contact pin 1 is also formed with press portions 1c pressed by a cam portion 3a formed to a movable plate 3. The cam portion 3a is inserted into a pair of press portions 1c thereby to lower the movable plate 3 in a state shown in FIG. 7A. When the movable plate 3 is moved downward, the paired press portions 1c are widened, and under this state, the connection pin 2 is inserted into a space between the paired contact portions 1b through an insertion hole 4a formed to a cover 4.
With reference to FIG. 7B, when the movable plate 3 is moved upward, the cam portion 3a is also moved upward and the connection pin 2 is then clamped by the paired contact portions 1b thereby to establish an electrical connection.
According to the structure mentioned above, the IC package can be mounted to or dismounted from the IC socket without using any insertion or withdrawal force only by moving up and down the movable plate 3 after projecting the IC package, thus improving working efficiency.
However, in such known structure, since a pair of contact portions 1b are widened by inserting the cam portion 3a of the movable plate 3 into the space between the paired press portions 1c of each contact pin 1, it is necessary to insert the cam portion 3a into the space between the paired press portions 1c at the time of arranging the contact pin 1 and the movable plate 3, which results in less assembling workability and in increasing of the operating force of the movable plate 3, thus being inconvenient and providing a problem.